Tuesday, February 20, 2018

Lab report: Thermoregulation in animals

Introduction:
Living organisms exist in habitats where the temperature ranges from 115 C in volcanic vents to -40 C at the poles. An organism’s temperature varies according to the amount of heat it gains and the amount of heat it loses. If heat gain is greater than heat loss, the temperature of the organism will rise and vice versa. To maintain a stable body temperature, an organism needs to balance its heat gain with its heat loss. Thermoregulation is the process by which animals maintain an internal temperature within a tolerable range. It contributes to homeostasis and involves anatomy, physiology and behavior. The experiment is conducted to study the effects of exercise on the breathing rate and body temperature of a human. It can be done by measuring the number of breathing rate during resting state an after a workout. Breathing rate is also known as respiration rate. It is measured by counting the number of breathes for one minute by counting the number of times the chest rises. For adults, the normal breathing rate is 12-18 breaths per minute. People who are ill, such as those with lung or heart disease, may have a change in breathing rate. Other factors that may affect breathing rates are carbon dioxide and concentration which causes a change in pH value of the blood. Carbon dioxide concentration may increase during exercises which use a lot of energy. The rate of respiration increases to provide more energy for the body to do work. This results in an increase in CO2 level as glucose is broken down into ATP and CO2. Drugs and alcohol such as narcotic pain reliever and sedative may depress the activity of the respiratory system. On the other hand, the temperature of the student is also measured before and after the workout using a thermometer.

Most body heat is generated in the deep organs, especially the liver, brain, and heart, and in contraction of skeletal muscles. Humans have been able to adapt to a great diversity of climates, including hot humid and hot arid. High temperatures pose serious stresses for the human body, placing it in great danger of injury or even death. For humans, adaptation to varying climatic conditions includes both physiological mechanisms resulting from evolution and behavioral mechanisms resulting from conscious cultural adaptations. The physiological control of the body’s core temperature takes place primarily through the hypothalamus, which assumes the role as the body’s “thermostat”. This organ possesses control mechanisms as well as key temperature sensors, which are connected to nerve cells called thermoreceptors. Thermoreceptors come in two subcategories; ones that respond to cold temperatures and ones that respond to warm temperatures. Scattered throughout the body in both peripheral and central nervous systems, these nerve cells are sensitive to changes in temperature and are able to provide useful information to the hypothalamus through the process of negative feedback, thus maintaining a constant core temperature.
There are four avenues of heat loss: convection, conduction, radiation, and evaporation. If skin temperature is greater than that of the surroundings, the body can lose heat by radiation and conduction. In stuffy and hot conditions, the only means by which the body can rid itself of heat is by evaporation. So, when the surrounding temperature is higher than the skin temperature, anything that prevents adequate evaporation will cause the internal body temperature to rise. During intense physical activity (e.g. sports), evaporation becomes the main avenue of heat loss. Humidity affects thermoregulation by limiting sweat evaporation and thus heat loss.

Hypothesis: I think that exercising does affect your pulse rate and will increase the amount pumps (the bumps you feel) because when you exercise your body has to pumps more blood. This is because when you exercise, the cells that are in your muscles need more energy to move. Your muscles get this energy from respiration. This chemical reaction uses up oxygen to release energy from glucose. This travels in the blood so if your muscles need more oxygen and glucose, they get it from the blood. So now we know that when you exercise, your body pumps more blood, which makes your pulse rate faster. Also when you have did a lot of exercise you can feel your pulse rate in your neck beating really fast. I think that my pulse rate will take about four/five/six minutes for it to return back to normal.

Hypothesis. Exercising increases breathing rate and body temperature in humans. Thermoregulation occurs in animals to maintain an internal temperature within a tolerable range.

Discussion:
Based on the result of the experiment, the number of breaths per minute is higher after the exercise than at rest. This is because doing exercises requires energy. The energy is obtained in the form of ATP through cellular respiration. The amount of CO2 production increases which lowers the pH value in the blood. This changes is detected by the chemoreceptor in the aorta and carotid arteries. A signal is sent to the breathing center of the medulla oblongata. An impulse is sent to the heart which increases heart rate. The blood with CO2 is brought faster to the lungs. Besides, an impulse also sent to the breathing musculature which increases breathing rate so that CO2 can be exhaled more rapidly. The body temperature of the student also increases after the exercise. This is because the by-product respiration is carbon dioxide, water and heat. During exercise, your body produced more heat than normal because cellular respiration increases. One of the safety measures taken while conducting this experiment is making sure that the individuals with identified health issues do not take part. This is because some health problems can be exacerbated by physical activities. We also had to ensure that the activity does not become competitive to reduce the risk of the activity causing damage. The site for the exercise chosen should also be safe. It should be well-constructed and stable. For example, when using a staircases, they students are instructed to use the handrail and ensure by supervision that this is obeyed. Apart from that, doing low impact exercise as described in this procedure should be safe for most students. Besides, students are required to wear appropriate outfits to avoid tripping or injuries.
During exercise, muscle cells use more oxygen and produce more carbon dioxide. Breathing rate increases so that more oxygen is taken into the lungs and more carbon dioxide is removed from the lungs. Heart rate increases so that more blood travels to the lungs to pick up more oxygen and deliver more carbon dioxide.

Possible sources of error
Miscounting the breathing rate. You shouldn’t define your own breathing rate by simply counting it. This is because as when we are aware of it, our breathing will be more deep and slow. The temperature taken may be inaccurate because it is the surface temperature and not the core temperature. This is because surface temperature is more susceptible to changes in the surrounding. The temperature taken may also be wrong because it is taken before the reading becomes constant, that is after hearing the ‘beep’ sound.

Suggestions on improving the experiment
Ask someone else to count your breathing rate. The person has to sit upright and the number of times the chest rises and falls are counted during one minute. The person also has to breathe normally. To improve the accuracy of the result, the measurement is taken three times to get an average result. Before taking the temperature measurement, dirt or hair should be removed from the forehead.

Validity:
 -More trials preformed could help the development of a more clear trend throughout the data
-Everyone using the same amount of weights, and doing the same type of lifting could eliminate the chances of one person working/exercising harder than another 
-Using a more accurate tool to measure the amount of time, such as a stopwatch, could improve the validity of the experiment because it would ensure that all of the volunteers are exercising and resting for the same amounts of time.

Conclusion
The hypothesis is accepted. Thermoregulation occurs in animals to maintain the internal temperature at a tolerable range. Exercising also increases the rate of breathing and temperature.

a)
Elephants:
- skin that is several sizes too big for its body. Heat is lost through the skin so the more skin, the better.
- has wrinkles, higher surface area exposed to the environment, excess heat is lost
- cool down in muddy water: mud collects in their folds and holds moisture near the skin when they leave the pool. The moisture gradually evaporates and cools the body due to mud’s high heat of vaporization
- elephant’s ears: radiate a lot of heat. When it is hot, blood vessels in the ears open and allow blood to cool as it flows within the paper thin skin. They flap their ears to cool the blood. The cool blood travels through the rest of its system, cooling its body and brain

Penguin:
- they stick together; in brutal winds, they huddle in large groups and take turn standing in the middle, the insulation of others help reduce heat loss by almost half
- feathers are densely packed, overlapping and waterproof. Can control the feathers individually. When the temperature drops, it lifts its feather upright, trapping a layer of insulating air around their body
- feet are small and lined with fat, rocking back on their heel-> minimize the contact of skin expose to ice
- as their blood circulates their body, the absorbs some of the heat before it reaches the feet

b) pH, concentration of CO2

c) Medulla oblongata regulates the rate and depth of breathing in response to ph changes in the cerebrospinal fluid and the pons regulates the tempo.The medulla oblongata is located in the brain stem, anterior to (in front of) the cerebellum.

d) Aorta and carotid artery- chemoreceptor (next to the respiratory center)
Central chemoreceptors of the central nervous system which is located near the brain stem in the medulla oblongata of the base of the brain. Peripheral chemoreceptor which is located in the aortic and carotid arteries. Furthermore, the peripheral is located in the arteries. Lastly, stretch receptors in the wall of bronchi and bronchioles.

1. Central chemoreceptors: These are located on the ventrolateral surface of medulla oblongata and detect changes in the pH of spinal fluid. They can be desensitized over time from chronic hypoxia (oxygen deficiency) and increased carbon dioxide.
2. Peripheral chemoreceptors: These include the aortic body, which detects changes in blood oxygen and carbon dioxide, but not pH, and the carotid body which detects all three. They do not desensitize, and have less of an impact on the respiratory rate compared to the central chemoreceptors.

e) normal CO2 level, physical activity increasesm cellular respiration increases, CO2 production increases, medulla oblongata stimulated, impulse sent, heart rate increasesm( breathing rate increases), blood with CO2 brought faster to the lungs ( CO2 exhaled more quickly)

exercise, high blood CO2 levels, drop in pH, detected by chemoreceptors, medulla stimulates increased rate and depth of breathing, increased rate of removal of CO2 from the body, blood CO2 levels fall, pH of the blood returns to normal

Breathing involves both voluntary and incoluntary actions. During exercise, the level of CO2 increases, the blood becomes more acidic. Chemoreceptors detect the low pH at the medulla obloganta. The carotid and aortic bodies and feeback is fiven to the breathing or respiratory center, The medulla responds by sending more frequent impulses to the intercostal muscle and diaphragm to increse the rate and depth of breathing.

Conclusion:
Another process that could have been used to measure the external and internal effects of exercise on the body could be to also measure the body temperature before and after the exercise is preformed. This could be a good variable to measure because often the amount of perspiration found on a body is a result of the internal and external body temperature. The relationship between the perspiration level and the body temperature is that they are both negative feedback. After exercise, the body tries to return to homeostasis; so when the body temperature increases due to exercise, the body perspires to cool off and return to its regular temperature, which is considered negative feedback.
The body needs energy for all kind of activities. When the body is resting, it needs lower amount of energy. But the more demanding activities we are doing, the more energy is needed. The main source of energy is carbohydrate and fat. The fat and carbohydrates are transformed by the ‘citric acid cycle’ into energy. The chemical energy is transferred to a substance that is called ATP (adenosine triphosphate). The ATP is a small package of energy that is used by the cells. In aerobic respiration oxygen is needed. The waste products are water, carbon dioxide and heat. The oxygen (O2) and carbon dioxide (CO2) is transported to/from the cells by the hemoglobin in the blood from/to the lungs. It is in the lungs, in the border between the capillaries and the alveoli, where the gases are exchanged by diffusion. The heart is the pump which makes the blood circulate in the body. And our breathing enables new air (with O2) to enter the lungs by inhaling and get rid of the old air (with CO2) by exhaling. Therefore with more demanding exercises (eg. running) more energy is needed and therefore also more oxygen is needed (in the citric acid cycle) and more carbon dioxide is produced. Therefore the heart and breathing rate is becoming higher to enable the transportation of carbon dioxide and oxygen.
Normal resting heart rate for an untrained man is 70 - 75 bpm. And it's lower for people that are well trained, it can be low as 25 bpm. And for old people it is higher. Normal breathing rate/min is 13 - 16
With this lab I want to find out how activities affect the heart and breathing rate in humans.
Conclusion:
The aim of this lab was to find out how activities affect the heart and breathing rate in a human. In my lab, I can easily see that the heart and breathing rate become higher during activity.
My data isn't 100% reliable because that measurement that I used wasn’t so good, eg. I measured for 15s and then I multiplied it by 4. If I would make a more accurate lab, I would measure in 60s. Or if even more correct, I could measure for 120s and divide by 2. It would be more accurate if I did like this, because when I measured for 15s and multiplied it by 4, it might be up to 2 heartbeats wrong when I started to measure and up to 2 heartbeats wrong in the end, then I multiply it by 4, so I could get up to 16 heartbeats wrong per minute. But if I measure for 60s, it could be up to 2 wrong in the beginning and up to 2 wrong in the end, which would mean that I would only get up to 4 heartbeats wrong per minute. Eg. if the accurate heartbeat/min is 70, it would be somewhere between  54 bpm and 86 bpm if I measured in 15s, if I measured in 60s it would be somewhere between 66bpm and 74bpm (which is much more reliable).
If I would do the lab even more accurate, I could use a professional pulse and breathing meter and have a treadmill for the testpersons to run on, so the testpersons would make exact the same activity.
In this lab the resting heart rate and the resting breathing rate were much higher than normal. The reason for this was probably that I didn’t measured the real resting rate for pulse and breathing. The persons was probably not relaxed. So in next lab I would make sure that the persons are relaxing.
It would be interesting to measure the heart and breathing rate on a smoker or a person that has certain health problems as eg. asthma, or a person that lives in a place where the environment is polluted, and how they respond to exercise, and compare to my results.In these persons, the gas exchange is slower, and smoking also has that negative effect that the hemoglobin can bind less oxygen because of it is occupied of carbon monoxide (CO). So if I would make a new study with persons in this group, I would probably get the results that their heart will beat faster and they will have much harder to make exercices.
According to the literature obesity, alcohol and drugs can affect a person’s heart and breathing rate. For example alcohol depresses both heart and breathing rate, which makes it harder to make exercices. Some drugs (medicines) can change the heart rate or make it easier to breath, eg. asthma drugs (eg. ventolin) make the muscles around the bronchi relax so that the tubes open and it is easier to breathe. Other drugs as nitroglycerine is used in angina pectoris and it makes the arteries around the heart becoming broader and let more blood pass to the heart and lower the heart rate.
When we don’t use the energy sources (fat, carbohydrates and proteins) that we eat, they get stored as glycogen and fat. If there is too big excess of energy sources, one become fat. Fat people have more mass and weighs more than not fat people, so they also need more energy and oxygen to do activities. Too much fat in the diet stops muscle cells to take up glucose from the blood and makes the cells to slow down the release of needed energy.
Discussion:
During exercise the body exhales more carbon dioxide than it would when it is at the state of rest. Exhaling more carbon dioxide is a result of the body taking in more oxygen, which results in the body taking in more breaths and the heartbeat to rise. In the results, all of the students exhaled more oxygen after exercising than they did while at rest. This is proven by the solution changing color when a certain amount of carbon dioxide was blown into it. The color change proves the students exhaled more while exercising. While the students were exercising, the body began to use up energy and look for a source to supply that energy. By breathing in more oxygen, the body is getting more oxygen to its cells, which lowers the heart rate and improves circulation for more energy. When one exercises, their body needs more energy. In order to obtain this energy, the body's breathing rate goes up, thus causing the body to exhale more carbon dioxide. This energy that the body gets from breathing in more air is used by the body’s muscles. Once the muscles are supplied with oxygen, it allows the body to break down stored up glucose. This is how the body supplies itself with enough energy to keep contracting.
Conclusion:
In this lab, students learn about carbon dioxide production levels as a result from different heart and breathing rates, which are altered by exercise. As the body exercises, the body must pump more blood, which carries oxygen, to the muscles. During exercise, a cellular respiration takes place in the muscles and carbon dioxide is the product, raising the levels of carbon dioxide in the body. The carbon dioxide is released from the body through exhaled air, thus there is more of it after a person exercises. Understanding why carbon dioxide levels rise and being able to test them is important to understanding biological processes.

Referencing
Boundless n.d, ‘Respiratory system’, viewed on 20th May 2017, https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/respiratory-system-22/respiration-control-212/chemoreceptor-regulation-of-breathing-1039-6384/
CYR, B 2014, ‘What effect does exercise have on your body temperature?’, viewed on 23rd May 2017, http://www.livestrong.com/article/380666-what-effect-does-exercise-have-on-your-body-temperature/
John Hopkins University n.d., http://www.hopkinsmedicine.org/healthlibrary/conditions/cardiovascular_diseases/vital_signs_body_temperature_pulse_rate_respiration_rate_blood_pressure_85,P00866/
Kutti, A n.d., ‘Respiration lab - Heart and breathing rate during activity’, viewed on 21st May 2017,
http://www.science123.n.nu/respiration
Mdco n.d., ‘Thermometer’, viewed on 22nd May 2017, http://www.mdco.gov.hk/english/emp/emp_gp/files/thermometer_eng.pdf
Nullfield Foundation 2011, ‘Observing the effects of exercise on the human body’, viewed on 22nd May 2017, http://www.nuffieldfoundation.org/practical-biology/observing-effects-exercise-human-body
Normal breathing n.d.http://www.normalbreathing.com/index-rate.php
Williams, G (2000), Advanced biology for you (p.311-313), (1st edition), England: Stanley Thornes Ltd

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